Baffle structure for oil circuit breaker tank



Nov. 17, 1964 J. R. MCcLouD 3,157,769

BAFFLE STRUCTURE FOR OIL CIRCUIT BREAKER TANK Filed April e, 1962 2 Sheets-Sheet 1 Nov. 17, 1964 J. R. MccLouD 3,157,769

BFFLE STRUCTURE FOR OIL CIRCUIT BREAKER TANK Filed April e, 1962 2 Sheets-Sheet 2 e; /INVENTOR JAMES l?. McC'OO m 5 BY Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsyivania Fiied Apr. 6, 1962, Ser. No. 155,685 3 Ciaims. (Cl. 20d- 15%) My invention relates to a novel construction for oil circuit breakers which permits the formation of an inexpensive, highly reliable system which could operate at ratings of the order of 14.4 kilovolts at 5 G0 mva.

The invention more speciiically is comprised of a plurality of novel features which cooperate with one another in the formation of a desirable unitary device, but any of the features could be used alone.

The first feature of the novel invention is the provision of a novel liner for the interior of the oil circuit breake tank. Liners of this type are shown in my copending application Serial No. 67,125, led November 3, 1960, entitled Three Phase Oil Circuit Breaker and assigned to the assignee of the instant invention, wherein the liners were dropped into the tank 'with four liner sections appropriately bolted to one another so that they have extending portions which extend between adjacent interrupters within a common tank.

In accordance with the present invention, the liners are not secured to one another, but are secured to a novel angle member contained in the tank wall which gives the liners superior rigidity at their free edges, and securely positions the liners within the tank.

Thus, one object of the present invention is to provide a novel improved liner construction for oil circuit breaker tanks.

A further object of the invention is to provide a novel construction for oil circuit breaker tanks wherein the free edges of insulation barriers between interrupters in a common 'tank are held securely.

A further feature of the invention is in the formation of the head of the top frame assembly. Generally, oil circuit breakers of the type to which the invention applies are formed of a main tank body which contains a dielectric medium such as oil and which receives a top frame assembly which carries the interrupters to be contained within the oil filled tank. The top frame assembly has a spherically shaped head portion which receives insulator bushings and through which insulator bushings pass.

It has been thought necessary in the past that this spherical head have a relatively short radius. Because of this, current transformers which seat beneath the head and around the bushings which pass through the head must be provided with special support structures, since the current transformers will not sit iiush against the head portion and are not tangent to the head portion. For example, it has been necessary to bump or iiatten the spherical head portions adjacent the insulation bushing supports and current transformers to make them tangent to the bushing mounting flange.

In accordance with the present invention, the spherical head is made to have a relatively large radius of the order of 48 inches, whereby the head will have a suiiciently dat surface to receive current transformers without the requirement of additional relativelyexpensive support structure. That is, the radius is such that it is tangent to the mounting ilange of the entrance bushing. This makes the long axis of the bushing at 90 to the head, creating an area suitable to seat thetransformer.

Moreover, this relatively large diameter head portion is made of a separate section which can be secured to a ring assembly. An identical ring assembly may then be l United States Patent O provided with a head of selected material, depending upon the current rating of the unit. y

By way of example, the spherical head may be of stainless steel where high current ratings of tl e order of amperes are to be used, whereby the stainless steel will have a suiiiciently resistivity to limit eddy currents to prevent excessive heating.

At lower current ratings of the order of 600 amperes, however, where eddy current heating is less severe, a head of identical configuration can be used, but of normal steel material. Thus, the material of the head is chosen in resistivity in accordance with the current rating of the unit.

Accordinglr, a further object of this invention is to provide a novel head portion for the top frame assembly which is exchangeable with other head portions of difierent materials, depending upon the current rating of the unit.

Another object of this invention is to utilize a high resistivity material for the head of the top frame assembly to reduce eddy current losses.

A further object oi this invention is to simplify the current transformer support on the head or" the top trame assembly for current transformers carried by the bushings entering the top trarne assembly.

A further obiect of this invention is to simplify current transiormer supports for oil circuit breakers by providing a large radius head port; n for the top frame assembly which is tangent to the mounting flange of the entrance As pointed out above, the oil circuit breaker is usually formed of a lower tank portion and a top frame assembly which is'received by the tank with me top trarne assembly carrying the interrupters. it is generally necessary that the tank can be removed from the top frame assembly so that the interrnpters may be inspected. To this end, the top frame assembly is provided with a lower ring which has an annular groove therein which receives a gasketing material. The upper rim of the tank then seats within this ring, and the two sections must be clamped together.

i have found a novei manner for forming this clamping arrangement wherein a lower ring secured to the top trame assembly is provided w threaded bosses disposed around the periphery orc the ring. These bosses are exposed externally of the diameter of the annular groove which receives the top of the tank. rihe tank is then provided with appr iate lugs winch are in cooperating position with the secured to the Lower ring of the top assembly.l Thus, a tank bolt inserted from beneath the lug be easily sed through the tank bolt lug and into engagement witn the tank bolt boss on the top frame assembly.

Accordingly, a further `object of this invention is to provide a novel method of clamping the top frame assembly to the tank of an oil circuit breaker.

These and other objects of my invention will become apparent from the following descrietion when taken in connection with the drawings, in which:

FGURE 1 shows a plan view of the interrupters carried from the top frame assembly of Ian oil circuit breaker with the tank of the circuit breaker cut away to show the inner portions thereof.

FIGURE 2 is a plan view of `the oil circuit breaker of FIGURE 1 when seen from an angle 9G displaced from the angle of FIGURE 1.

FIGURE 3 is a cross-sectional view of FIGURE 1 taken across the lines 3-3 in FGURE 1 to illustrate the tank liners and insulation barriers between interrupters.

FIGURE 4 is a side cross-sectional view through the top trame assembly to illustrate the interchange-able top plate of the top trame assembly.

FlGURF is a side cross-sectional View of FIGURE 4 when taken across the lines 5-5 in FIGURE 4, and further shows in exploded view the top of the tank to illus* trate the novel clamping means of the invention.

Referring now to FIGURES l and 2, I have illustrated therein a typical oil circuit breaker assembly which contains the novel features of the invention. In many respects, the Ioil circuit breaker assembly of FIGURES 1 and 2 is similar to that of my copending application Serial No. 67,125 Three Fhase Oil Circuit Breaker, and refer* ence is made thereto for several details of construction which need not be given here.

Generally, in FlGURES 1 and 2, l have shown an oil circuit breaker tank .itl which will be lled with oil and which receives six inter-rupters lll through ld (FGURE 3) Winch correspond to two series connected interrupters for each phase :of a three-phase system. Interrupters of ,the type which could be used in FIGURES l vand 2 are shown, for example, in copending applications Serial No. 2,390, now Fatent No. 3,128,360, issued April 7, 1964; Serial Number 2,530, now abandoned; and Serial No. 88,349, and need not be described in detail here. FIG- URE l shows four of the six interrupters `as interrupters lll, l2, l 'and 1.a. lnterrupters i3 and lll are also seen in FlGURE 2 along with a fifth interrupter l5.

lt will be noted that interrupters lll. and lll `are connected in series with a first phase, interrupters l2 and 1 3 are in series with a second phase, and interrupters l5 and lo correspond to a third phase.

Each of the interrupters are carried by an `appropriate :insulator bushing such as bushings Ztl, 2,2 and in FEGURE l which have interrupters lll, 1.2, 1l?, and ld at the lower ends thereof. The bushings extend through openings in the top plate 24 lof the top frame 25, and are mechanicallycarried by the top frame assembly 25.

rThe system is operated from an operating mechanism which could be of the type shown in copending applica Serial No. 157,352, filed December 6, 1961, entitled Moto-r Operated Spring Mechanism, inthe name of .lames-R. McCloud, and assigned to the assignee of the present invention, with `an appropriate system of linkages 3@ which could be ofthe type shown in copending application Serial No. 67,125, being connected to the three lift rodsl, 32 `and 33 of FlGURE 2. The lift rods are provided with appropriate guide structures which lare also fully described in copending application Serial No. 67,125, and terminate with respective crossbars 3d, 35 and Zit (FIGURES 2 and 3) which carry bayonet-type contacts at their opposite ends.

Thus, crossbar 35 carried bayonet contacts /lll and il which yare connected in series through crossbar 35 and cooperate with stationary contacts contained at the top of interrupters lll and ld. respectively. ln a simidar manner, bayonet contacts and 413 of FlGURE l cooperate with interruptor chambers l2 and i3, while similar bayonet contacts such as the bayonet contact le on cross# v when the circuit breaker is closed. To this end, and in FIGURE 1, it Ais `seen that bushing Ztl has a current transformer 5@ thereon which is supported between the bottom of top plate 2d and a bracket l5l. which is also carried from top plate 24 by studs from plate 2d.

In the past, it has been necessary to flatten the portion of the top plate Which'is adjacent the current transformer location so that the current transformer can be appropriaely S'cured in pOsOui In accordance with the present invention, however, l form the top plate 2t of a sutliciently large diameter so that the 'area receiving the top of current transformer 5t) land the other current transformers of the remaining bushings Will be suitliciently flat to inherently serve as a tangent :support surface. Thus, the support structure for the current transformer is considerably simplified, and the cost of the unit is decreased.

As a further feature of the invention, and as is discussed in copending )application Serial No. 67,125, it is desirable that the insulation barriers extend between the adjacent interruptcrs to prevent an expanding gas bubble generated during operation of the interrupters from connecting two :adjacent interrupters whereby a phase-tophase failure may occur.

ln accordance with the present invention, and as is .best seen in FIGURE 3,'they inner walls of tank l@ are provided with angles oil, til, 62 and 63 which are welded to the tank walls of tank lll. Elongated fiber liners dit, 65', and o7 are then bolted to the angles, as illustrated by bolts 68 and 69 for angle 6l, whereby the free ends of the liners formed in the cloverleaf pattern of FIGURE 3 extend between the interrupters of adjacent phases.

Accordingly, this novel construction permits secure bolting between the tank wall and the liners, which gives the liners great rigidity at their free edges. Moreover, it eliminates the need for passing bolts through the tank wall vfor receiving the liners, as has been the practice in the past.

The invention further provides simplicity in the formation o t the top frame assembly 25. More specifically, and referring to FIGURES 4 and 5, the top frame assembly is formed of the top plate 24- previously described as having a relatively large radius and a ring ill which is welded to the top plate 2d along the seam 7l. The ring itl then receives a lower plate 72 having an annular groove 73 therein which, as seen in FlGURE 5, receives the upper end '74 of tank wall lll. Clearly, an appropriate gasketing ring (not shown) will be contained within groove 73 to provide a tight seal between the tcp frame assembly 25 and the tank lll. Y

l have discovered that the resistivity of top plate 24- should be relatively high for applications wherein the rated current is of the order of 1200 amperes, since eddy currents in a relatively low resistivity top plate at these relatively high currents can cause excessive heating. When, however, the current rating is decreased, the eddy currents can be largely ignored. However, the same physv ical size unit may bef used within a wide range of currents so that a unitary top frame assembly would require a large inventory where different resistivity materials are to be used, depending upon the rating of the unit.

In accordance with the present invention, the top plate 2d is a component part of the top frame assembly, and it would only be necessary to stock the same top plate 2d in different materials with the remainder of the top frame assembly beingthe same.

Accordingly, in current applications of the order of 1260 amper'es, the top plate 24 will'be made of stainless steel which has a higher resistivity than normal steel, while it can be of normal steel Where the current rating is of the order of 600 amperes.

As a further feature of the invention, and as is specilically illustrated in FIGURE 5, l have provided a novel means for securing the topV frame assembly to the tank which eliminates the previous need for a rolled ring, but permits the casting of a common lower ring '73. More specitically, and as illustrated in FIGURE 5, the lower ring '73 is provided with a plurality of bosses such as bosses Stl andV 3l of FIGURE 5 where, for example, eight bosses are placed around the lower edge of ring73. These bosses are cast in such a position as to align with tank bolt lugs such as lugs S2 and S3 which are welded to the upper end of tank wall lll, and register with the various bosses around the lower surface of ring 73.

In order to secure tank lll to the top frame assembly 25, it is only necessary to bring the tank lo upwardly so thatr its end 7d engages groove 73, whereupon the tank 5 boit lugs align With tank boit bosses, Tank bolts such as bolts 84 and 85 can then be threaded into the tapped opening Within the bosses so that the tank 1t) is securely fastened to top frame assembly 25.

Although I have described preferred embodiments of my novel invention, many variations and modifications will new be obvious to those skilled in the art, and 1 prefer, therefore, to be limited not by the specific disclosure herein but only by the appended claims.

I ciaim:

1. 1n an oil circuit breaker; a tank containing oil, a plurality of interrupter structures supported Within said tank, a plurality of insulation sheets interposed between adjacent interrupters of said plurality of interrupters, and a support means for supporting said plurality of insulation sheets; said support means comprising angle members secured to the interior surface of said tank and extending parallel to the axis of said tank; said angle members having their apex facing toward the center of said tank; each of said plurality of said sheets having a portion thereof extending along the interior of said tank and having an intermediate portion of said sheet secured to one face of a respective angle member; the remaining portion of each t5 of said insulation sheets extending from its said respective angle member and toward the interior of said tank.

2. The device substantially as set forth in claim 1 wherein six interrupters deline said plurality of interrupters; each ot' said six interrupters having axes parallel to the axis of said tank; said six interrupters being arranged to form three pairs of series connected devices.

3. The device substantially as set forth in claim 2 wherein said plurality of insulation sheets comprises four adjacent insulation sheets defining at least four extending sections; said at least four extending sections extending between adjacent interrupters of different pairs of said pairs of interrupters.

References Qited in the tile of this patent UNTED STATES PATENTS 1,015,613 Burnham Jan. 23, 1912 1,643,444 Burnham Sept. 27, 1927 1,687,560 Hilliard Oct. 16, 1928 1,719,269 Kelle July 2, 1929 2,028,963 Wood Jan. 28, 1936 2,252,983 Rossman Aug. 19, 1941 2,283,874 Nye May 19, 1942 2,290,560 Hernan Iuly 21, 1942 

1. IN AN OIL CIRCUIT BREAKER; A TANK CONTAINING OIL, A PLURALITY OF INTERRUPTER STRUCTURES SUPPORTED WITHIN SAID TANK, A PLURALITY OF INSULATION SHEETS INTERPOSED BETWEEN ADJACENT INTERRUPTERS OF SAID PLURALITY OF INTERRUPTERS, AND A SUPPORT MEANS FOR SUPPORTING SAID PLURALITY OF INSULATION SHEETS; SAID SUPPORT MEANS COMPRISING ANGLE MEMBERS SECURED TO THE INTERIOR SURFACE OF SAID TANK AND EXTENDING PARALLEL TO THE AXIS OF SAID TANK; SAID ANGLE MEMBERS HAVING THEIR APEX FACING TOWARD THE CENTER OF SAID TANK; EACH OF SAID PLURALITY OF SAID SHEETS HAVING A PORTION THEREOF EXTENDING ALONG THE INTERIOR OF SAID TANK AND HAVING AN INTERMEDIATE PORTION OF SAID SHEET SECURED TO ONE FACE OF A RESPECTIVE ANGLE MEMBER; THE REMAINING PORTION OF EACH OF SAID INSULATION SHEETS EXTENDING FROM ITS SAID RESPECTIVE ANGLE MEMBER AND TOWARD THE INTERIOR OF SAID TANK. 